Legionella in the dental office

Contamination of dental unit water lines (DUWL) with Legionella pneumophila and Pseudomonas aeruginosa; A Middle East systematic review and meta-analysis

This review aimed to evaluate the contamination rate of dental unit waterlines (DUWL) with Pseudomonas aeruginosa and Legionella pneumophila in several countries in the Middle East.Literature search was conducted in databases such as PubMed, Scopus, Web of Science, and Google Scholar to gather studies published from the beginning of 2000 to 30th April 2020. Medical Subject Headings (MeSH) terms were; "Legionellosis"; "Legionnaire", "Legionellosis", "L. pneumophila", "dent", "dental", "dentistry", "Dental Unit Waterlines", "dental water", "DUWL", "Middle East", "P. aeruginosa", "Iran", "Turkey", "Iraq", and "Jordan". The search was independently conducted by two of the authors. Data was analyzed using Comprehensive Meta-Analysis software.Almost all studies included in this review reported a high rate of bacterial contamination of DUWL, which exceeded the current standard bacterial contamination level of <200 (CFU) mL-1 recommended by the American Dental Association (ADA). The combined prevalence of L. pneumophila from four countries (Iran, Jordan, Turkey, and Iraq) was 23.5% (95% Cl: 6.5-57.7), and the combined prevalence of P. aeruginosa was reported 21.7% (95% Cl: 7.1-50.1%).This study showed a high bacterial contamination rate of DUWL with opportunistic pathogens. So, it is recommended to prevent biofilm formation in DUWL, some measures should be extended by practical approaches allowing for water quality control and improvement on-site in the dental practices such as mobile filtration units, chlorination and disinfection chemicals.

Rates and predictors of exposure to Legionella pneumophila in the United States among dental practitioners: 2002 through 2012

BACKGROUND

In this study, the authors compared the odds of exposure to Legionella pneumophila among currently active dental practitioners with that of nonpractitioners and evaluated demographic and clinical practice predictors of exposure.

METHODS

The authors obtained demographic characteristics and dental practice behaviors from participants in the annual American Dental Association Health Screening Program survey administered from 2002 through 2012. The authors assayed serum samples obtained from participants for L pneumophila antibodies. The authors used an adjusted logit model to evaluate predictors of positive results.

RESULTS

Among 5,431 participants, approximately 10% were positive for L pneumophila, with no significant differences between dental practitioners and nonpractitioners. Geographic location was the only significant predictor of seropositivity, with no increased risk of being exposed to L pneumophila associated with age, race, sex, years in practice, hours of practice per week, use of barrier protection, or infection control practices.

CONCLUSIONS

Prevalence of L pneumophila antibodies was 10.4% among dental and nondental personnel. US Census division was the only significant predictor of seropositivity. The authors conclude that provision of dental care did not increase the risk of being exposed to Legionella.

PRACTICAL IMPLICATIONS

Dentists should be aware of the prevalence of Legionella species in their practice areas to understand their personal risk of developing an infection.